I. Field
The following relates generally to wireless communication, and more specifically to resource scheduling for wireless communication.
II. Background
Wireless communication systems are widely deployed to provide various types of communication content such as, e.g., voice content, data content, and so on. Typical wireless communication systems can be multiple-access systems capable of supporting communication with multiple users by sharing available system resources (e.g., bandwidth, transmit power). Examples of such multiple-access systems can include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, and the like.
Generally, wireless multiple-access communication systems can simultaneously support communication for multiple mobile devices. Each mobile device can communicate with one or more base stations via transmissions on forward and reverse links. The forward link (or downlink) refers to the communication link from base stations to mobile devices, and the reverse link (or uplink) refers to the communication link from mobile devices to base stations. Further, communications between mobile devices and base stations can be established via single-input single-output (SISO) systems, multiple-input single-output (MISO) systems, multiple-input multiple-output (MIMO) systems, and so forth.
A MIMO system employs multiple (NT) transmit antennas and multiple (NR) receive antennas for data transmission. A MIMO channel formed by the NT transmit and NR receive antennas may be decomposed into NS independent channels, which are also referred to as spatial channels, where NS≦min{NT, NR}. Each of the NS independent channels corresponds to a dimension. The MIMO system can provide improved performance (e.g., higher throughput and/or greater reliability) if the additional dimensionalities created by the multiple transmit and receive antennas are utilized.
Wireless messages are typically sub-divided in time, frequency, according to codes, and so on, to convey information. For instance forward link messages comprise at least one time segment (e.g., a time slot, superframe, etc., of various lengths of time) segmented into one or more preambles and several time sub-segments (e.g., time subslots, time frames). The preamble carries acquisition and control information, while the various other time frames carry traffic, such as voice information pertinent to a voice call, data packets pertinent to a data call or data session, or the like. Acquisition information can be utilized by mobile terminals within a given mobile network cell to identify transmitting base stations within the sector. Control channel information provides commands and other instructions for decoding received signals.
In various mobile communication systems (e.g., ultra mobile broadband [UMB], third generation partnership project [3GPP] long term evolution [LTE—or just LTE]), preambles or similar structures can similar information as described above, or different information. For instance, a preamble in some systems can carry synchronization or acquisition pilots to identify a remote transmitter and establish timing for decoding functions. In addition, the preamble can carry control information enabling a remote terminal to search for a cell at power-up, determine initial parameters of a cell necessary for making handoff decisions, establishing communication with a network, and demodulating non-control channels. Other functions can include specifying formats of traffic channels for some wireless systems. Typically, a preamble is set apart from a traffic-related portion of a wireless signal to facilitate distinction of application-related information and control information at a receiver. Thus, the receiver can monitor control portions to identify whether a signal contains traffic pertinent to a receiving device, without having to monitor the traffic portions themselves. Because the control portion is typically only a small fraction of the total signal, receiver devices can significantly reduce processing requirements and power consumption by monitoring a signal preamble to determine whether relevant information is contained in the signal. Employing control channels for wireless signaling therefore leads to more effective communication, as well as improved mobility by extending battery life for mobile devices.
In a planned deployment of wireless access networks, air signal interference can result from transmissions by access points (e.g., base stations) as well as access terminals. Interference within a particular cell can be caused by access points or access terminals in neighboring cells, for instance. Typically, planned deployments are managed by positioning base stations according to transmission power and expected interference. However, interference can still occur between the transmitters, especially when devices utilize high power transmissions. To reduce interference, interference reduction signals can be utilized within an access network. A base station receiving an interference reduction signal can reduce its transmit power or transmit power of access terminals (ATs) served by the base station. However, where un-planned or semi-planned wireless access point deployments exist, additional interference reduction mechanisms can be helpful for reducing interference from transmitters whose location or transmit power are not precisely known by the access network.